title: A 13C NMR spectrometric method for the determination of intramolecular δ13C values in fructose from plant sucrose samples.
abstract: Recent developments in (13) C NMR spectrometry have allowed the determination of intramolecular (13) C/(12) C ratios with high precision. However, the analysis of carbohydrates requires their derivatization to constrain the anomeric carbon. Fructose has proved to be particularly problematic because of a byproduct occurring during derivatization and the complexity of the NMR spectrum of the derivative. Here, we describe a method to determine the intramolecular (13) C/(12) C ratios in fructose by (13) C NMR analysis of the acetyl-isopropylidene derivative. We have applied this method to measure the intramolecular (13) C/(12) C distribution in the fructosyl moiety of sucrose and have compared this with that in the glucosyl moiety. Three prominent features stand out. First, in sucrose from both C(3) and C(4) plants, the C-1 and C-2 positions of the glucosyl and fructosyl moieties are markedly different. Second, these positions in C(3) and C(4) plants show a similar profile. Third, the glucosyl and fructosyl moieties of sucrose from Crassulacean acid metabolism (CAM) metabolism have a different profile. These contrasting values can be interpreted as a result of the isotopic selectivity of enzymes that break or make covalent bonds in glucose metabolism, whereas the distinctive (13) C pattern in CAM sucrose probably indicates a substantial contribution of gluconeogenesis to glucose synthesis.
authors.affiliation: Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes, France.
authors.forename: Alexis
authors.initials: A
authors.lastname: Gilbert
authors.affiliation: Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes, France.
authors.forename: Virginie
authors.initials: V
authors.lastname: Silvestre
authors.affiliation: Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes, France.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Robins
authors.affiliation: Plant Biology Institute (IBP), CNRS UMR 8618, University of Paris Sud 11, F-91405 Orsay, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Tcherkez
authors.affiliation: Interdisciplinary Chemistry: Synthesis, Analysis, Modelling (CEISAM), University of Nantes-CNRS UMR 6230, 2 rue de la Houssinière, BP 92208, F-44322 Nantes, France.
authors.forename: Gérald S
authors.initials: GS
authors.lastname: Remaud
mesh_terms: D053000:Analytic Sample Preparation Methods; D031230:Ananas / Q000737:chemistry*; D001628:Beverages / Q000032:analysis*; D002247:Carbon Isotopes / Q000032:analysis; D005632:Fructose / Q000031:analogs & derivatives* / Q000737:chemistry*; D005947:Glucose / Q000031:analogs & derivatives / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods* / Q000592:standards; D015203:Reproducibility of Results; D013395:Sucrose / Q000737:chemistry
chemical_list: C546613:3,5,6-triacetyl-1,2-O-isopropylidene-alpha-D-glucofuranose; D002247:Carbon Isotopes; D005632:Fructose; D013395:Sucrose; D005947:Glucose